This is a multicenter, randomized, controlled trial to evaluate the efficacy, safety and tolerance of the combination of HIV hyperimmune globulin (HIVIG) (administered during pregnancy and to the newborn within 12 hours of birth) and ZDV (administered intrapartun and to the newborn for 6 weeks following birth), compared to IVIG and ZDV administered similarly, for the reduction of vertical HIV transmission in HIV-infected pregnant women who are receiving ZDV during pregnancy for medical indications.